Nowadays in the field of aircraft, an architecture comprising an elongated fuselage in which passengers or cargo are transported and a wing attached to the fuselage in a central portion of the fuselage between the front extremity of the fuselage and the rear extremity of the fuselage is widely used and may be considered conventional.
This conventional architecture is used widely because of the advantages it offers both in terms of both aerodynamics and in operational terms for the aeroplane.
For aerodynamic purposes, the elongated fuselage provides a usable volume that may be substantial while retaining a reduced midship frame, while the aspect ratio may be relatively large, both of these factors helping to limit aerodynamic drag.
Operationally, the elongated shape of the fuselage means that a sufficient number of exits can easily be provided to enable rapid passenger embarkation and disembarkation operations and still ensure the number of emergency exits required according to regulations, since the length on the fuselage occupied by the wing arrangement is moderate relative to the length of the fuselage itself and therefore not obstructive.
Although this conventional architecture is very frequently used in the field of transport aircraft, it still comprises two quite distinct families in respect of the propulsion engines.
In the first family, the propulsion engines are mounted under the wing, most often two or four engines are disposed symmetrically relative to the fuselage, as with the Airbus A320 (two engines) or A380 (four engines) for example, and in a second family the propulsion engines are mounted at the rear and on either side of the fuselage, as on the SE210 Caravelle aeroplane, for example, and possibly inside or above the fuselage.
In order to deliver the thrust required by transport aircraft, as soon as the mass of the aeroplane exceeds a few tens of tons, the engines used are turbojet engines or turboprop engines having turbines as power generators, and which most often entail the use of blowers with a large diameter or propellers with varying degrees of complexity.
In order to contain debris, which may arise during the operation of the engine, designers occasionally resort to shielding, which is fitted around ducted rotating parts such as blowers, but when the energy involved is considerable this method of containing engine debris becomes impractical, that is to say the additional weight becomes unacceptable.
In order to prevent sensitive parts of the aeroplane from being damaged, for example the parts containing flight controls or vital structures, the engines are located in such positions that the possible trajectories of the engine debris cannot bring it into contact with said sensitive parts or cause damage that would endanger the aeroplane.
In the case of engines mounted at the rear of the aeroplane, the problem is more difficult to address due to the concentration of flight controls in the rear section of the fuselage, which is relatively small and is also where the aeroplane empennages are located in conventional architectures, the horizontal and vertical stabilising empennages.
Nowadays, designers have overcome the problems of installing rear jet engines by a positioning, particularly a longitudinal positioning of the jet engines that is limiting but possible due to the relatively small dimensions of said jet engines, and/or because the energy of debris that might be associated with the engine is limited, and by multiplying the flight control systems.
Unfortunately, the appearance for various reasons of engines that have rotating parts with larger diameters, particularly engines with unducted counter-rotating propellers, which in some respects seem to be simpler to install at the rear of the fuselage than under the wing, simply reintroduces the problem of dealing with debris.
The designs for installing such engines consist in known manner of replacing the conventional jet engines with these engines by adapting the support pylons whose function is to ensure a distance between the axis and the engine according to the diameter of the rotating parts, as in U.S. Pat. No. 5,443,229, for example, but these solutions are able to simply contain the consequences of the breakup of a rotating part of the engine, which is likely to cause damage to the aeroplane flight control systems, particularly the rear empennages or a section of the structure of the empennages or the rear fuselage, damage that must then be taken into account at the design stage.
The implementation of such solutions is therefore very expensive and complex, and is the source of various less than optimal conditions, particularly in terms of weight and aerodynamics.
In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.